Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Reexamination Certificate
2001-12-17
2003-10-28
Barts, Samuel (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
C568S367000, C568S377000, C568S816000, C568S834000, C435S067000, C424S489000, C424S491000, C424S498000
Reexamination Certificate
active
06639113
ABSTRACT:
The invention relates to a process for producing dry powders of one or more oxygenated carotenoids, in particular dry powders, comprising carotenoids selected from the group consisting of astaxanthin, canthaxanthin, lutein, zeaxanthin, citranaxanthin and &bgr;-apo-8′-carotinic acid ethyl ester.
The carotenoid class of substances is classified into two main groups, carotenes and xanthophylls. In contrast to the carotenes, which are purely polyene hydrocarbons, for example &bgr;-carotene or lycopene, in the xanthophylls, oxygen functions, such as hydroxyl, epoxy and/or oxo groups also occur. Typical representatives of this group are, inter alia, astaxanthin, canthaxanthin, lutein and zeaxanthin.
Oxygenated carotenoids are widespread in nature and occur, inter alia, in corn (zeaxanthin), in green beans (lutein), in capsicum (capsanthin), in egg yolks (lutein) and in crabs and salmon (astaxanthin), in which case they give the characteristic coloration to these foods.
These polyethers which are not only accessible by synthesis, but can also be isolated from natural sources, are important pigments for the food and feed industries and for the pharmaceutical sector and, in the case of astaxanthin, are active compounds having provitamin A activity in salmon.
Xanthophylls, like all carotenoids, are insoluble in water, whereas in fats and oils, however, only low solubility is found. This restricted solubility and the high sensitivity to oxidation oppose direct use of the relatively coarse-grained products obtained in synthesis in the pigmentation of foods and feeds, since the substances in coarsely crystalline form give only poor pigmentation results. These effects which are disadvantageous for the practical use of xanthophylls are pronounced in particular in aqueous medium.
Only by means of specifically produced formulations in which the active compounds are present in finely divided form and, if appropriate, are protected against oxidation by protective colloids, can improved color yields be achieved in the direct pigmentation of foods. In addition, these formulations used in feeds lead to a higher bioavailability of the xanthophylls and thus indirectly to improved pigmentation effects, for example in the pigmentation of egg yolks or fish.
To improve the color yields and to increase the absorbability and bioavailability, various methods have been described which all have the purpose of decreasing the crystallite size of the active compounds and bringing it to a particle size range of smaller than 10 &mgr;m.
Numerous methods, inter alia described in Chimia 21, 329 (1967), WO 91/06292 and in WO 94/19411, make use of grinding carotenoids by means of a colloid mill and thus achieve particle sizes of from 2 to 10 &mgr;m.
In addition there are a number of combined emulsification/spray-drying processes, as described, for example, in DE-A-12 11 911 and EP-A-0 410 236.
According to European patent EP-B-0 065 193, finely divided pulverulent carotenoid preparations are prepared by dissolving a carotenoid in a volatile water-miscible organic solvent at elevated temperatures, if appropriate under elevated pressure, precipitating out the carotenoid by mixing with an aqueous solution of a protecting colloid and then spray-drying it.
A similar process for producing finely divided pulverulent carotenoid preparations is described in EP-A-0 937 412, using water-immiscible solvents.
However, in the case of the nanoparticulate active compound dispersions of xanthophylls produced in accordance with EP-B-0 065 193, the following phenomena may frequently be observed.
The aqueous xanthophyll-containing active compound dispersions are frequently, in particular during concentration, colloidally unstable. As a result of flocculation of the active compound particles which in part sediment, in part cream in the course of this, further conversion of the dispersion into a dry powder is no longer possible.
In the case of xanthophylls containing carbonyl functions, in addition, the gelatin used as protecting colloid can crosslink, so that a gel is formed that can no longer be redispersible and which also cannot be converted into a dry powder.
Thus the high requirements made of xanthophyll-containing formulations with respect to pigmenting action and bioavailability cannot always be met, owing to the problems with the abovementioned process described.
A disadvantage of gelatins is also their highly adhesive property. Using the drying methods customary for liquid systems, such as spray-drying, or spray-fluidized-bed drying, filament formation or encrustations can occur when gelatin-containing products are used.
In addition, gelatin-containing products have constantly decreasing consumer acceptance.
Frequently, only relatively low concentrations of fat-soluble substances can be incorporated into other frequently used protecting colloids, such as gum arabic, starch, dextrins, pectin or tragaxanth. Furthermore, gum arabic, in the past, as a result of harvest failures, has not always been available, nor in sufficient quality.
Synthetic colloids such as polyvinylpyrrolidone or partially synthetic polymers such as cellulose derivatives also exhibit restricted emulsifying capacity and are not always accepted, especially in the foods sector.
DE-A-44 24 085 describes the use of partially hydrolyzed soybean proteins as protecting colloids for fat-soluble active compounds. The soybean proteins disclosed here have a degree of hydrolysis of from 0.1 to 5%.
A disadvantage of the abovementioned soybean proteins is frequently their poor water solubility, inadequate emulsifying properties and their tendency to crosslink, which is undesirable, particularly for the production of dry powders which can be redispersed in water.
It is an object of the present invention, therefore, to propose processes for producing dry powders of oxygenated carotenoids using protecting colloids which do not have the abovementioned disadvantages of the prior art.
We have found that this object can be achieved, surprisingly, by a process for producing dry powders of one or more oxygenated carotenoids by
a) dispersing one or more oxygenated carotenoids in an aqueous molecular dispersion or colloidal dispersion of a protecting colloid and
b) converting the dispersion formed into a dry powder by removing the water and any solvents additionally used and drying, in the presence or absence of a coating material,
which comprises using as protecting colloid in process step a) at least one partially hydrolyzed soybean protein having a degree of hydrolysis greater than 5%.
According to the invention, the protecting colloid is a partially hydrolyzed soybean protein that has a degree of hydrolysis (DH) greater than 5%, preferably from 6 to 20%, particularly preferably from 6 to 12%, very particularly preferably from 6 to 9%. The degree of hydrolysis “DH” is defined as follows:
DH
=
Number
of
peptide
bonds
cleaved
Total
number
of
peptide
bonds
×
100
%
The degree of hydrolysis can be determined by the “pH-Stat-Method”, as described by C. F. Jacobsen et al. in “Methods of Biochemical Analysis”, Vol. IV, pp. 171-210, Interscience Publishers Inc., New York 1957.
The partial hydrolysis is generally performed enzymatically, with as suitable enzymes, proteases from plants, microorganisms and fungi, or animal proteases, coming into consideration. Preferably, the partial hydrolysis is performed using the plant protease bromelain.
The soybean proteins used are customarily commercial soybean protein isolates and soybean protein concentrates with protein contents of 70 to 90% by weight, the remaining 10 to 30% by weight being more or less undefined other plant constituents, soybean proteins which are preferably used in this context are non-genetically-modified soybean proteins.
The soybean protein-isolates are incubated with the enzyme in an aqueous medium, preferably at from 50 to 70° C. and at pHs from 7 to 9. The suitable ratio of
Auweter Helmut
Hinz Willy
Lüddecke Erik
Pfeiffer Angelika-Maria
Runge Frank
Barts Samuel
BASF - Aktiengesellschaft
Keil & Weinkauf
Witherspoon Sikarl A.
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